Big Data has been all the rage. But fast data, even if it is small, can be more valuable than complicated masses of information.

Here’s why: All the focus on “bigger is better” has overlooked the fact that most Big Data segments have not been validated with a business application or value.

Instead, for marketers looking to make an impact by the end of their day, thinking in micro slices instead of terabytes can be more valuable. As a marketer, even if my army of analysts could crunch and return an actionable insight from all of that data, I would still have to be able to use it in time for it to be actionable with my customer.

That time constraint is real. And that means data that is at your fingertips when you need it can be more valuable than any Big Data you might collect, because delivering a better customer experience is limited to what you can access in a short window of time.

Of course, I’m not suggesting you do away with all longer-term analysis. Those kinds of analytics can help you find the right streams to access and work with, and also can help you build out robust programs that identify valuable customers. But what I am saying is that, at the end of the day, the only thing that matters to you and your job today is what you will be able to leverage in real time.

So, how can you access real-time data? Look for data sources that can be accessed via your Web browser, including these three:

1) Your First-Party Data

The primary and most valuable data set you can access, first-party data encompasses transactional and other customer-level profile information you have on your customers. It could also include your own off-line segmentation analysis that allows you to map a customer to a customer profile around which you build your marketing programs. This can also include your analytics or other on-site tracking data, which can deliver behavioral insight to your consumers. This data can be difficult to export from its current environment due to the ad hoc nature of the data, but, if possible, look at ways to make this information accessible to your digital sites.

2) Third-Party Data

A consumer’s broader Web browsing and buying history can now be accessed in session to provide you with more context on their likes and habits. Data management platforms (DMPs) and other data aggregators are accelerating this offering and, just as importantly, the availability of this type of data. This is invaluable in the context of new visitors who you know nothing about historically.

3) Real-Time Behavior

Let’s not forget what our customers are telling us with each click. We get enamored with our predictive modeling to the point that we do not see the tell-tale signs as they are happening. Take the time to stop, look, and react. Your analytic tools, personalization tools, and other software-as-a-service (SaaS) platforms can help you trigger alternate site experiences based on every click you see.

For example, a customer headed to Miami for Labor Day weekend is telling a travel site every detail needed to curate the rest of that experience, a bathing suit category visit just told you today’s buying impulse, and so on. From imagery to content to add-ons to navigation, don’t ignore what your customer is telling you.

You will find some immediate ways to create better customer experiences and drive conversions and revenue by analyzing the value of your accessible data. The key is to use your data to make your customers’ interactions better. Helping your customers win in their session is value delivered, indeed.

Editor’s Note: This blog post originally appeared in ClickZ, where Nathan is a guest columnist.